gh-134584: Eliminate redundant refcounting from `_STORE_ATTR_WITH_HINT` (GH-142767)

Signed-off-by: Manjusaka <me@manjusaka.me>

diff --git a/Include/internal/pycore_opcode_metadata.h b/Include/internal/pycore_opcode_metadata.h
index c0e3725db1d7cae822d5e58f4f05fcdd5e23912c..a4f1f50e96d6d181817781ab03109886f54bf148 100644 (file)
--- a/Include/internal/pycore_opcode_metadata.h
+++ b/Include/internal/pycore_opcode_metadata.h
@@ -1484,7 +1484,7 @@ _PyOpcode_macro_expansion[256] = {
     [STORE_ATTR] = { .nuops = 1, .uops = { { _STORE_ATTR, OPARG_SIMPLE, 3 } } },
     [STORE_ATTR_INSTANCE_VALUE] = { .nuops = 4, .uops = { { _GUARD_TYPE_VERSION_AND_LOCK, 2, 1 }, { _GUARD_DORV_NO_DICT, OPARG_SIMPLE, 3 }, { _STORE_ATTR_INSTANCE_VALUE, 1, 3 }, { _POP_TOP, OPARG_SIMPLE, 4 } } },
     [STORE_ATTR_SLOT] = { .nuops = 3, .uops = { { _GUARD_TYPE_VERSION, 2, 1 }, { _STORE_ATTR_SLOT, 1, 3 }, { _POP_TOP, OPARG_SIMPLE, 4 } } },
-    [STORE_ATTR_WITH_HINT] = { .nuops = 2, .uops = { { _GUARD_TYPE_VERSION, 2, 1 }, { _STORE_ATTR_WITH_HINT, 1, 3 } } },
+    [STORE_ATTR_WITH_HINT] = { .nuops = 3, .uops = { { _GUARD_TYPE_VERSION, 2, 1 }, { _STORE_ATTR_WITH_HINT, 1, 3 }, { _POP_TOP, OPARG_SIMPLE, 4 } } },
     [STORE_DEREF] = { .nuops = 1, .uops = { { _STORE_DEREF, OPARG_SIMPLE, 0 } } },
     [STORE_FAST] = { .nuops = 1, .uops = { { _STORE_FAST, OPARG_SIMPLE, 0 } } },
     [STORE_FAST_LOAD_FAST] = { .nuops = 2, .uops = { { _STORE_FAST, OPARG_TOP, 0 }, { _LOAD_FAST, OPARG_BOTTOM, 0 } } },

diff --git a/Include/internal/pycore_uop_ids.h b/Include/internal/pycore_uop_ids.h
index 5519e14e9020c4dfd0b229e63bb93db280f73432..8678ccf5e1b823b37824b5e466364a2c726a3dbf 100644 (file)
--- a/Include/internal/pycore_uop_ids.h
+++ b/Include/internal/pycore_uop_ids.h
@@ -1038,7 +1038,7 @@ extern "C" {
 #define _STORE_ATTR_r20 1231
 #define _STORE_ATTR_INSTANCE_VALUE_r21 1232
 #define _STORE_ATTR_SLOT_r21 1233
-#define _STORE_ATTR_WITH_HINT_r20 1234
+#define _STORE_ATTR_WITH_HINT_r21 1234
 #define _STORE_DEREF_r10 1235
 #define _STORE_FAST_r10 1236
 #define _STORE_FAST_0_r10 1237

diff --git a/Include/internal/pycore_uop_metadata.h b/Include/internal/pycore_uop_metadata.h
index f0af30df0634e839c8a698d05df207039512d7d9..c6d3670b193123277f79306c54a3708b2b4902de 100644 (file)
--- a/Include/internal/pycore_uop_metadata.h
+++ b/Include/internal/pycore_uop_metadata.h
@@ -1837,7 +1837,7 @@ const _PyUopCachingInfo _PyUop_Caching[MAX_UOP_ID+1] = {
         .entries = {
             { -1, -1, -1 },
             { -1, -1, -1 },
-            { 0, 2, _STORE_ATTR_WITH_HINT_r20 },
+            { 1, 2, _STORE_ATTR_WITH_HINT_r21 },
             { -1, -1, -1 },
         },
     },
@@ -3546,7 +3546,7 @@ const uint16_t _PyUop_Uncached[MAX_UOP_REGS_ID+1] = {
     [_GUARD_DORV_NO_DICT_r22] = _GUARD_DORV_NO_DICT,
     [_GUARD_DORV_NO_DICT_r33] = _GUARD_DORV_NO_DICT,
     [_STORE_ATTR_INSTANCE_VALUE_r21] = _STORE_ATTR_INSTANCE_VALUE,
-    [_STORE_ATTR_WITH_HINT_r20] = _STORE_ATTR_WITH_HINT,
+    [_STORE_ATTR_WITH_HINT_r21] = _STORE_ATTR_WITH_HINT,
     [_STORE_ATTR_SLOT_r21] = _STORE_ATTR_SLOT,
     [_COMPARE_OP_r21] = _COMPARE_OP,
     [_COMPARE_OP_FLOAT_r01] = _COMPARE_OP_FLOAT,
@@ -4786,7 +4786,7 @@ const char *const _PyOpcode_uop_name[MAX_UOP_REGS_ID+1] = {
     [_STORE_ATTR_SLOT] = "_STORE_ATTR_SLOT",
     [_STORE_ATTR_SLOT_r21] = "_STORE_ATTR_SLOT_r21",
     [_STORE_ATTR_WITH_HINT] = "_STORE_ATTR_WITH_HINT",
-    [_STORE_ATTR_WITH_HINT_r20] = "_STORE_ATTR_WITH_HINT_r20",
+    [_STORE_ATTR_WITH_HINT_r21] = "_STORE_ATTR_WITH_HINT_r21",
     [_STORE_DEREF] = "_STORE_DEREF",
     [_STORE_DEREF_r10] = "_STORE_DEREF_r10",
     [_STORE_FAST] = "_STORE_FAST",

diff --git a/Lib/test/test_capi/test_opt.py b/Lib/test/test_capi/test_opt.py
index 3ae87fead94d3b6e87c965a75a976b49418a31be..bed8d1d52e93b2ab2812b5f7207289575ecfbb8f 100644 (file)
--- a/Lib/test/test_capi/test_opt.py
+++ b/Lib/test/test_capi/test_opt.py
@@ -2612,6 +2612,26 @@ class TestUopsOptimization(unittest.TestCase):
         self.assertNotIn("_POP_TOP", uops)
         self.assertIn("_POP_TOP_NOP", uops)
 
+    def test_store_attr_with_hint(self):
+        def testfunc(n):
+            class C:
+                pass
+            c = C()
+            for i in range(_testinternalcapi.SHARED_KEYS_MAX_SIZE - 1):
+                setattr(c, f"_{i}", None)
+
+            for i in range(n):
+                c.x = i
+            return c.x
+        res, ex = self._run_with_optimizer(testfunc, TIER2_THRESHOLD)
+        self.assertEqual(res, TIER2_THRESHOLD - 1)
+        self.assertIsNotNone(ex)
+        uops = get_opnames(ex)
+
+        self.assertIn("_STORE_ATTR_WITH_HINT", uops)
+        self.assertNotIn("_POP_TOP", uops)
+        self.assertIn("_POP_TOP_NOP", uops)
+
     def test_store_subscr_int(self):
         def testfunc(n):
             l = [0, 0, 0, 0]

diff --git a/Misc/NEWS.d/next/Core_and_Builtins/2025-12-16-05-24-24.gh-issue-134584.tJ1usH.rst b/Misc/NEWS.d/next/Core_and_Builtins/2025-12-16-05-24-24.gh-issue-134584.tJ1usH.rst
new file mode 100644 (file)
index 0000000..aa096fc
--- /dev/null
+++ b/Misc/NEWS.d/next/Core_and_Builtins/2025-12-16-05-24-24.gh-issue-134584.tJ1usH.rst
@@ -0,0 +1 @@
+Eliminate redundant refcounting from ``_STORE_ATTR_WITH_HINT``.

diff --git a/Python/bytecodes.c b/Python/bytecodes.c
index f126c44749254b29a2700ae4537168fb7ea8b3ae..25e730f7e6e8ec4ac6de40ebd5103edebb735d41 100644 (file)
--- a/Python/bytecodes.c
+++ b/Python/bytecodes.c
@@ -2603,7 +2603,7 @@ dummy_func(
             _STORE_ATTR_INSTANCE_VALUE +
             POP_TOP;
 
-        op(_STORE_ATTR_WITH_HINT, (hint/1, value, owner --)) {
+        op(_STORE_ATTR_WITH_HINT, (hint/1, value, owner -- o)) {
             PyObject *owner_o = PyStackRef_AsPyObjectBorrow(owner);
             assert(Py_TYPE(owner_o)->tp_flags & Py_TPFLAGS_MANAGED_DICT);
             PyDictObject *dict = _PyObject_GetManagedDict(owner_o);
@@ -2633,14 +2633,16 @@ dummy_func(
             // old_value should be DECREFed after GC track checking is done, if not, it could raise a segmentation fault,
             // when dict only holds the strong reference to value in ep->me_value.
             STAT_INC(STORE_ATTR, hit);
-            PyStackRef_CLOSE(owner);
+            o = owner;
+            DEAD(owner);
             Py_XDECREF(old_value);
         }
 
         macro(STORE_ATTR_WITH_HINT) =
             unused/1 +
             _GUARD_TYPE_VERSION +
-            _STORE_ATTR_WITH_HINT;
+            _STORE_ATTR_WITH_HINT +
+            POP_TOP;
 
         op(_STORE_ATTR_SLOT, (index/1, value, owner -- o)) {
             PyObject *owner_o = PyStackRef_AsPyObjectBorrow(owner);

diff --git a/Python/executor_cases.c.h b/Python/executor_cases.c.h
index e64934483a2841fad84ff44154cd2429f58dcb2f..55c4495f2dc59d6cd27aa35cf315f11310a68bd8 100644 (file)
--- a/Python/executor_cases.c.h
+++ b/Python/executor_cases.c.h
@@ -8775,11 +8775,12 @@
             break;
         }
 
-        case _STORE_ATTR_WITH_HINT_r20: {
+        case _STORE_ATTR_WITH_HINT_r21: {
             CHECK_CURRENT_CACHED_VALUES(2);
             assert(WITHIN_STACK_BOUNDS_IGNORING_CACHE());
             _PyStackRef owner;
             _PyStackRef value;
+            _PyStackRef o;
             _PyStackRef _stack_item_0 = _tos_cache0;
             _PyStackRef _stack_item_1 = _tos_cache1;
             oparg = CURRENT_OPARG();
@@ -8848,16 +8849,19 @@
             FT_ATOMIC_STORE_PTR_RELEASE(ep->me_value, PyStackRef_AsPyObjectSteal(value));
             UNLOCK_OBJECT(dict);
             STAT_INC(STORE_ATTR, hit);
-            stack_pointer += -2;
+            o = owner;
+            stack_pointer[-2] = o;
+            stack_pointer += -1;
             ASSERT_WITHIN_STACK_BOUNDS(__FILE__, __LINE__);
             _PyFrame_SetStackPointer(frame, stack_pointer);
-            PyStackRef_CLOSE(owner);
             Py_XDECREF(old_value);
             stack_pointer = _PyFrame_GetStackPointer(frame);
-            _tos_cache0 = PyStackRef_ZERO_BITS;
+            _tos_cache0 = o;
             _tos_cache1 = PyStackRef_ZERO_BITS;
             _tos_cache2 = PyStackRef_ZERO_BITS;
-            SET_CURRENT_CACHED_VALUES(0);
+            SET_CURRENT_CACHED_VALUES(1);
+            stack_pointer += -1;
+            ASSERT_WITHIN_STACK_BOUNDS(__FILE__, __LINE__);
             assert(WITHIN_STACK_BOUNDS_IGNORING_CACHE());
             break;
         }

diff --git a/Python/generated_cases.c.h b/Python/generated_cases.c.h
index cd52a20be9fd119a2f12b039340b0a4e72db9274..3c18960a39d7d71f0471eeed5bd95249de28050b 100644 (file)
--- a/Python/generated_cases.c.h
+++ b/Python/generated_cases.c.h
@@ -10747,6 +10747,7 @@
             static_assert(INLINE_CACHE_ENTRIES_STORE_ATTR == 4, "incorrect cache size");
             _PyStackRef owner;
             _PyStackRef value;
+            _PyStackRef o;
             /* Skip 1 cache entry */
             // _GUARD_TYPE_VERSION
             {
@@ -10812,13 +10813,23 @@
                 FT_ATOMIC_STORE_PTR_RELEASE(ep->me_value, PyStackRef_AsPyObjectSteal(value));
                 UNLOCK_OBJECT(dict);
                 STAT_INC(STORE_ATTR, hit);
-                stack_pointer += -2;
+                o = owner;
+                stack_pointer[-2] = o;
+                stack_pointer += -1;
                 ASSERT_WITHIN_STACK_BOUNDS(__FILE__, __LINE__);
                 _PyFrame_SetStackPointer(frame, stack_pointer);
-                PyStackRef_CLOSE(owner);
                 Py_XDECREF(old_value);
                 stack_pointer = _PyFrame_GetStackPointer(frame);
             }
+            // _POP_TOP
+            {
+                value = o;
+                stack_pointer += -1;
+                ASSERT_WITHIN_STACK_BOUNDS(__FILE__, __LINE__);
+                _PyFrame_SetStackPointer(frame, stack_pointer);
+                PyStackRef_XCLOSE(value);
+                stack_pointer = _PyFrame_GetStackPointer(frame);
+            }
             DISPATCH();
         }
 

diff --git a/Python/optimizer_bytecodes.c b/Python/optimizer_bytecodes.c
index e9e5bd5db1f04f01ce62df440248ce4f46fb0772..31ec88e1c84912d9dbe001aafe57efbed3b15113 100644 (file)
--- a/Python/optimizer_bytecodes.c
+++ b/Python/optimizer_bytecodes.c
@@ -104,6 +104,11 @@ dummy_func(void) {
         o = owner;
     }
 
+    op(_STORE_ATTR_WITH_HINT, (hint/1, value, owner -- o)) {
+        (void)value;
+        o = owner;
+    }
+
     op(_STORE_FAST, (value --)) {
         GETLOCAL(oparg) = value;
     }

diff --git a/Python/optimizer_cases.c.h b/Python/optimizer_cases.c.h
index 9c61b06d5f7eedcfa9e5e19e83b4ca75401e024b..6fde87a17fbaa32546b2acd40659efcc3104b6d8 100644 (file)
--- a/Python/optimizer_cases.c.h
+++ b/Python/optimizer_cases.c.h
@@ -1699,8 +1699,17 @@
         }
 
         case _STORE_ATTR_WITH_HINT: {
-            CHECK_STACK_BOUNDS(-2);
-            stack_pointer += -2;
+            JitOptRef owner;
+            JitOptRef value;
+            JitOptRef o;
+            owner = stack_pointer[-1];
+            value = stack_pointer[-2];
+            uint16_t hint = (uint16_t)this_instr->operand0;
+            (void)value;
+            o = owner;
+            CHECK_STACK_BOUNDS(-1);
+            stack_pointer[-2] = o;
+            stack_pointer += -1;
             ASSERT_WITHIN_STACK_BOUNDS(__FILE__, __LINE__);
             break;
         }